A macro language stores repeated text with the encoding k[substring], meaning the enclosed substring is repeated k times. Substrings may contain plain lowercase letters and may themselves contain further nested k[...] groups. There is no whitespace, k is a positive integer (possibly multi-digit), and every group is well-formed and balanced.
For example, 2[ab] expands to abab, and 2[a3[b]] expands to abbbabbb. Print the fully expanded text.
Input format
Line 1: a non-empty encoded string using lowercase letters, digits, and the bracket characters [ and ].
Output format
A single line: the fully expanded text.
Constraints
- The encoded string contains between 1 and 3000 characters.
- Every repetition count is between 1 and 1000.
- The fully expanded text has at most 100000 characters.